The present invention is related to devices and methods for processing image data. More particularly, the present invention is related to devices and methods for processing image data in order to reduce undesirable contrast effects in displayed images, wherein in the image data may include red, green, blue, and/or white image data.
Liquid crystal display devices have been widely used in televisions, computer monitors, and mobile devices. Conventional RGB liquid crystal display devices may include red, green, and blue color elements for combining the three primary colors in various ways to present various colors in displayed images. For enhancing brightness of displayed images and/or for saving energy consumed by backlight modules of display devices, RGBW liquid crystal display devices that further include white color elements (e.g., pixels or sub-pixels having no color filters) have been implemented.
In RGBW devices, the white color elements may substantially enhance the brightness of white components and desaturated-color components in displayed images. Nevertheless, the brightness enhancement effect of the white color elements may substantially diminish for image components having colors exceeding 50% saturation, and the white color elements may have substantially no brightness enhancement effect on image components having pure 100% saturated colors, such as red, green, and blue. The disparity of the brightness enhancement effect may lead to undesirable contrast effects when saturated colors arc viewed in a displayed image simultaneously with peak white or desaturated colors that have received the effective brightness enhancing benefit of the white color elements. Saturated colors, especially “warm” colors such as yellow, orange, and red, may appear especially dark when displayed in an image having a very bright (e.g., white) reference.